Internal live loading packing gland

ABSTRACT

Live loading is applied on each end of both the secondary and the primary packing of a packing gland. After installing the primary packing assembly and a lantern ring, the primary packing is compressed to proper specifications. While the primary gland is so compressed, it is locked into place using lantern ring lock bolts. The secondary packing assembly and a follower are then installed. The secondary gland is also compressed to proper specifications and the follower secured in place. The lantern ring lock bolts are then removed, both internally and externally live loading the packing gland. A single assembly of the present live loaded packing can also be installed in the gland from the process side, eliminating the need for purging and resulting in a most efficient purgeless gland.

BACKGROUND OF THE INVENTION

This invention relates generally to packing glands and more particularlyconcerns live loading packing glands.

Presently known packing glands use a primary set of packing consistingof five to six rings of packing, a lantern ring followed by a secondaryset of packing consisting of five to six rings of packing and a followerto compress the packing. In some instances the follower is live loadedby springs or Beleville washers which maintain a constant pressure onthe packing and create a type of constant adjustment to the packing.

There are several problems with these glands. Due to the mass anddensity of packing materials, a maximum of five rings of packing can becompressed. Since the present live loading glands only apply a pressureto the outer end of the secondary packing, once the gland has beenpacked, neither the follower nor the live loading has the ability totighten or compress the primary packing.

Since the primary packing is not properly compressed, leakage in a valveincorporating the gland is prevented primarily by the secondary packinggland. During its initial life, the primary packing gland minimizes butdoes not eliminate leakage. During the continued life of the gland, asleakage continues, the seepage rate of the process into the glandincreases, further damaging the primary gland and increasing the rate ofseepage. This is especially true if the process employs highly corrosivecatalysts which accelerate erosion of both the gland and the stem whichit surrounds.

It is, therefore, an object of this invention to provide a packing glandthat makes effective use of its primary packing. It is a further objectof this invention to provide a packing gland in which the primary andsecondary packing are both compressed under relatively uniformcompression. A correlative object of this invention is to provide apacking gland which employs both internal and external glandcompression.

SUMMARY OF THE INVENTION

In accordance with the invention, live loading is applied on each end ofboth the secondary and the primary packing. To properly live load thepacking gland, a lantern ring is locked in place after the packing ofthe primary packing. After installing the primary packing assembly andthe lantern ring, the primary packing is compressed to properspecifications, which change with the size of the glands. While theprimary gland is compressed, it is locked into place using lantern ringlock bolts. The secondary packing assembly and follower are theninstalled. The secondary gland is compressed to the properspecifications and the follower secured in place. The lantern ring lockbolts are removed and replaced with vent valves. The packing gland isthus both internally and externally live loaded.

Furthermore, most glands utilize a purge medium to create a barrierbetween the regular packing and the process. But a single assembly ofthe present live loaded packing can be installed in the gland from theprocess side, eliminating the need for purging and resulting in a mostefficient purgeless gland.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings in which:

FIG. 1 is a sectional view taken along the longitudinal axis of thepreferred embodiment of the internal live loading packing gland; and

FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG. 1.

While the invention will be described in connection with a preferredembodiment, it will be understood that it is not intended to limit theinvention to that embodiment. On the contrary, it is intended to coverall alternatives, modifications and equivalents as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE INVENTION

Turning to FIG. 1, the preferred embodiment of the internal live loadingpacking gland is illustrated. A valve stuffing box cylinder or casingbox 11 extends from the valve bonnet 13 through a valve actuatormounting plate 15. A circular bore extends through the casing 11 and thebonnet 13 along a longitudinal axis 17 on which the valve stem (notshown) will be centered. Disposed along an interior surface of thecasing 11 is an annular stop 19, as shown proximate the bonnet 13. Inthe assembly of the packing gland, a stop ring 21 may be inserted intothe bore and seated on the annular stop 19. The first annular primarybias 23 is inserted against the stop ring 21 or the annular stop 19 ifthe stop ring 21 is not used. With the bias member 23 in place, theprimary packing is inserted into the bore. As shown, the primary packingconsists of five packing rings including the outside packing rings 25and the inside packing rings 27. A second annular primary bias 29 isthen inserted against the outermost outside packing ring 25. To completethe primary packing, a locking or lantern ring 31 is inserted against asecond annular primary bias 29.

As shown in FIG. 2, the locking ring 31 can be locked in place by one ormore set screws or locking bolts 33 set in threaded apertures in thecasing 11. Thus, with the primary packing gland and the locking ring 31loaded into the casing, the packing rings 25 and 27 and biases 23 and 29can be compressed between the stop 19 or stop ring 21 and the lockingring 31 to a preselected compressive load condition. The locking bolt orbolts 33 can then be tightened down on the locking ring 31 to secure thelocking ring 31 in place and maintain the preselected compression in theprimary packing gland. Once the primary packing gland has been sopacked, a first annular secondary bias 35 can be inserted in the boreagainst the locking ring 31. The secondary packing including outsidepacking rings 37 and inside packing rings 39 is then inserted into thebore. A second annular secondary bias 41 is then seated against theoutermost of the outside packing rings 37. A follower 43 is theninserted into the bore and seated against the second annular secondarybias 41. Now the secondary packing, including the biases 35 and 41 andpacking rings 37 and 39 are compressed between the locking ring 31 andthe follower 43 to a preselected compressive load condition. Thefollower 43 has a flange 45 through which bolts 47 extend so that thefollower 43 may be secured to the casing 11 to maintain the preselectivecompressive load condition in the secondary packing gland. With theprimary and secondary packing glands thus compressively loaded, thelocking bolt or bolts 33 may be withdrawn to release the locking ring 31to slide within the bore of the casing 11. The bolts 33 may be replacedwith vent valves (not shown), and, to this end the locking bolts 33 arepreferably set at a suitable angle, say 33° in relation to the diameterof the locking ring 31 which extends through the sealant inlet 49 andthe drain 51. The end result of this arrangement is that both theprimary and secondary packing glands are live loaded because they areeach provided with their own bias.

As shown, the casing 11 may also be provided with a sealant inlet 49 anda drain 51.

If it is desirable to employ a purgeless packing gland, then, as shown,a similar packing arrangement can be provided at the process end of thecasing 11. A spacing ring 53 may be inserted in the end of the bore tobe seated against the opposite side of the stop 19 as the primarypacking components. If the spacing ring 53 is employed, then a firstannular process bias 55 is inserted in the bore against the spacing ring53. Otherwise, the bias 55 will be seated against the stop 19. Theprocessed packing is then inserted in the bore, including outsideprocessed packing rings 57 and inside processed packing rings 59. Asecond annular process bias 61 is then inserted to complete the processpacking and a process follower, which may be the valve stem guardbushing 63 as shown, is inserted in the bore against the second processbias 61. The process packing, including the biases 55 and 61 and packingrings 57 and 59, may then be compressed between the spacing ring 53 orthe stop 19 and the process follower 63 to a preselected compressiveload condition. A flange 65 on the process follower 63 holds bolts 67which may be threaded into the casing 11 or the bonnet 13 as shown tosecure the process follower 63 in position and maintain the preselectivecompressive load condition in the process packing. As shown, the casing11 may include a vent 69 and a drain 71 extending therethrough to portsin the spacing ring 53.

As shown in FIG. 1, the biases 23, 29, 35, 41, 55 and 61 are singleBelleville washers having their outer diameter rims abutting theoutermost packing rings 25, 37 and 57 of the primary, secondary andprocess packing. Depending on the amount of compression desired, anumber of Belleville washers might be used to constitute each bias. Ifmore than one Belleville washer is used, the washers will be alternatelyinverted from those washers which are in abutment with the packingrings. The outer diameter rim of the abutting washer, however, must bein abutment with the packing rings so as to cause the packing rings tocompress inwardly toward the valve stem (not shown).

As shown in FIG. 1, two outside rings and three inside rings are used ineach packing. However, any number of one or more packing rings could beemployed. Furthermore, the primary, secondary and process packing in thesame valve could employ different numbers of washers and packing ringsin each packing. The application of each valve will dictate the numberof biases, the number of packing rings and the sizes of biases andpacking rings necessary for that valve. Moreover, the biases need notnecessarily be Belleville washers, but might be any resilientlycompressible member such as, for example, a helical compression spring.

Thus, it is apparent that there has been provided, in accordance withthe invention, an internal live loading packing gland that fullysatisfies the objects, aims and advantages set forth above. While theinvention has been described in conjunction with specific embodimentsthereof, it is evident that many alternatives, modifications andvariations will be apparent to those skilled in the art and in light ofthe foregoing description Accordingly, it is intended to embrace allsuch alternatives, modifications and variations as fall within thespirit of the appended claims.

What is claimed is:
 1. A packing gland comprising:a casing having acircular bore therethrough and an annular stop on an interior surface ofsaid bore; a first annular primary biasing means seated on said stop; anannular primary packing means seated on said first primary biasingmeans; a second annular primary biasing means seated on said primarypacking means; an annular locking means seated on said second primarybiasing means; a first annular secondary biasing means seated on saidlocking means; an annular secondary packing means seated on said firstsecondary biasing means; a second annular secondary biasing means seatedon said secondary packing means; an annular follower means seated onsaid second secondary biasing means; means for securing said lockingmeans to said casing with said primary packing and biasing meanscompressed between said stop and said locking means to a preselectedcompressive load condition; and means for securing said follower meansto said casing with said secondary packing and biasing means compressedbetween said locking means and said follower means to a preselectedcompressive load condition, said locking means securing means havingmeans accessible externally of said casing for releasing said lockingmeans to slide within said casing after said follower means securingmeans is secured.
 2. A packing gland according to claim each of saidbiasing means comprising a resiliently compressible member.
 3. A packinggland according to claim 1, each of said biasing means comprising atleast one belleville washer.
 4. A packing gland according to claim 3,each said washer in contact with one of said packing means having anouter rim in abutment therewith.
 5. A packing gland according to claim4, said washers of each of said biasing means having more than onewasher being alternately inverted from said abutting washer.
 6. Apacking gland according to claim each of said packing means comprisingat least one packing ring.
 7. A packing gland according to claim 1, saidlocking means comprising a ring and said locking ring securing meanscomprising a threaded locking bolt extending through said casing to saidring.
 8. A packing gland according to claim 7, said accessible meanscomprising a bolthead on said locking bolt.
 9. A packing gland accordingto claim 1 further comprising:a first annular process biasing meansseated on an opposite side of said stop from said first primary biasingmeans; an annular process packing means seated on said first processbiasing means; a second annular process biasing means seated on saidprocess packing means; an annular process follower means seated on saidsecond process biasing means; and means for securing said processfollower means to said casing with said process packing and biasingmeans compressed between said stop and said process follower means to apreselected compressive load condition.
 10. A packing gland according toclaim 1 further comprising:an annular spacing means seated on anopposite side of said stop from said first primary biasing means; afirst annular process biasing means seated on said spacing means; anannular process packing means seated on said first process biasingmeans; a second annular process biasing means seated on said processpacking means; an annular process follower means seated on said secondprocess biasing means; and means for securing said process followermeans to said casing with said process packing and biasing meanscompressed between said stop and said process follower means to apreselected compressive load condition.
 11. A packing gland according toclaim 10, said process follower means comprising a stem guide bushing.12. A packing gland according to claim 10 further comprising a bonnetabutting an end of said casing and said bore extending through saidbonnet, said process follower means being securable by said securingmeans to said bonnet.
 13. A packing gland according to claim 10, each ofsaid biasing means comprising a resiliently compressible member.
 14. Apacking gland according to claim 10, each of said biasing meanscomprising at least one belleville washer.
 15. A packing gland accordingto claim 14, each said washer in contact with one of said packing meanshaving an outer rim in abutment therewith.
 16. A packing gland accordingto claim 15, said washers of each of said biasing means having more thanone washer being alternately inverted from said abutting washer.
 17. Apacking gland according to claim 10, each of said packing meanscomprising at least one packing ring.